The present invention relates to a tightening device for footwear and a footwear provided with such tightening device.
In particular, the present invention relates to a tightening device for a sports footwear of the kind comprising a substantially rigid outer element and a substantially flexible inner element and a sports footwear of the kind comprising a substantially rigid outer element and a substantially flexible inner element provided with such tightening device.
Sports footwear are known comprising a substantially rigid outer element or shell and a substantially flexible inner element or liner which is at least partially housed inside the outer element. Ski boots are a clear example of sports footwear of this kind.
In this kind of sports footwear the inner liner with its upper part usually projects at least in sections from the upper edge of the outer shell.
Still according to the prior art, these sports footwear may include a tightening device provided near the upper end of the outer shell and of the inner liner for tightening the sports footwear around the user's leg. In particular, the tightening device can be made substantially as a ring and can include adjusting means for more or less limiting the width of the ring, so as to more or less tighten the sports footwear around the user's leg.
For example, U.S. Pat. No. 6,026,594 describes a tightening device comprising a strap element arranged for being attached frontally near the upper end of the cuff of a sports footwear (especially of a ski boot) and a pair of bands connected to the opposite ends of the strap element; the two bands can be linked to each other by means of a buckle so as to obtain a ring around the cuff of the sports footwear, and the position of the buckle can be adjusted so as to vary the width of the obtained ring and to tighten the tightening device on the cuff of the sports footwear. During use, with the tightening device being tensioned, the strap element exerts a pressure onto the cuff of the sports footwear surrounding the user's leg.
A disadvantage of this solution lies in the fact that the strap element exerts pressure directly onto the rigid outer shell of the sports footwear and only indirectly—through intermediation of the outer shell—onto the flexible inner liner, which limits the user's comfort.
This disadvantage is particularly detrimental when considering that in sports footwear comprising a rigid outer shell and a flexible inner liner, footwear comfort is provided mainly by the inner liner, whereas the outer shell has mainly the function of conferring structural strength to the footwear and of efficiently conveying forces from the user to the sports item.
A further disadvantage of the solution described above consists in that, in those areas where the inner liner projects from the outer edge of the outer shell, the strap element is not in contact with the footwear surface. Consequently the pressure is not uniformly distributed; rather, there are created discrete pressure points that are detrimental to the user's comfort.
U.S. Pat. No. 8,359,771 describes a solution in which the tightening device includes a strap element comprising a first element and a second element that are mutually separated and vertically superimposed on each other, wherein the upper element is configured and arranged so as so abut against the inner liner of the footwear and the lower element is configured and arranged so as to abut against the outer shell of the footwear. According to what is described, such solution allows on one hand to act directly both onto the outer shell and onto the inner liner and on the other hand to obtain a more uniform distribution of pressure.
However, this solution too is not free from drawbacks. In particular, the fact that the strap element comprises two distinct elements separated by an interposed gap causes poor stability of the tightening element and brings about the risk that the elements may move out of their correct position during use of the footwear.
This risk is particularly evident in the case of sports footwear, where during use the tightening device is exposed to continuous and intense stresses. Especially during sports practices, the small size of the two elements of the strap element and the presence of an open gap between them may cause misalignments, loss of proper adjustment and similar inconveniences.